Bubbling over the blood-brain barrier

From the ALS Research Forum by Amber Dance

How do you sneak past a barrier? Perhaps you hitch a ride with someone who’s allowed across. That’s one strategy scientists are considering to deliver biological therapeutics for nervous disorders such as ALS across the endothelial cells tightly lining the blood-brain barrier.

Exosomes, extracellular vesicles just 30-150 nanometers across, are increasingly recognized as an important player in the CNS, where they mediate communication between neurons and glia. They protect neurons and may even help axons regenerate (Lopez-Verrilli et al., 2013; Goncalves et al., 2015; Hervera et al., 2018).

Information Sharing. Researchers first turned to exosomes as a drug delivery vehicle due to their ability to transfer mRNAs and miRNAs between cells (Valadi et al., 2007). [Courtesy of Raposo and Stoorvogel, 2013, Journal of Cell Biology. CC BY 3.0.]

Moreover, these membrane-bound bubbles easily travel from the bloodstream into the brain and spinal cord. Bioengineers quickly sensed their potential. “This is just so great,” said Martin Fussenegger of ETH Zürich in Basel, Switzerland. “These exosomes just go across the blood-brain barrier.”

He and others are looking into ways to deliver therapies, such as mRNAs or enzymes, as exosome cargo into the brain to treat neurodegenerative disease.

“I believe exosomes are an exciting therapeutic modality that should see clinical deployment in the next few years,” said HaiFang Yin of Tianjin Medical University in China.

Oxford start-up Evox Therapeutics in England is banking on exosomes to treat rare neurological and neuromuscular diseases too.

“However, there are a number of hurdles that need to be overcome,” said Yin.

For treatments to be feasible, drug makers need reliable ways to load the cargo into exosomes at clinically meaningful dosages and deliver them to the right place. These vesicles will also need to be highly purified, clinical grade, and safe.

Scientists are beginning to overcome some of these obstacles…(read more)

Source – ALS Research Forum